AP Photos: Cities go dark for Earth Hour'

Onlookers watch Taipei 101 building as it turns its lights off to observe international "Earth Hour" campaign, Saturday, March 23, 2013, in Taipei, Taiwan. Around 100 people gathered outside the skyscraper Saturday, using energy saving LED lights to observe the global event that encourages people to turn off their lights for 60 minutes. (AP Photo/Wally Santana)

It’s something of a voluntary rolling blackout: Communities around the globe are going dark for an hour on Saturday evening as part of an initiative called “Earth Hour,” to raise awareness of climate change.

In more than 7,000 cities and towns across the planet, millions of residents are turning off their lights for an hour from 8:30 to 9:30 p.m. local time to show their environmental concern.